Many items come from the Library’s Leonard Bernstein Collection. Especially intriguing are “a series of letters written to his wife Felicia while she was visiting her family in Santiago, Chile, [where] Leonard Bernstein faithfully chronicles the show’s progress during the final weeks of rehearsal through the show’s out-of-town opening in Washington, D.C. The letters reveal Bernstein’s changing emotions about the show from frustration and agony to his final state of euphoria. ”